This invention relates to dielectri fluids for electrical capacitors, particularly metallized polypropylene (PP) film capacitors capable of operating under high AC voltage stress (above 1300 volts/mil).
There are many desirable properties of dielectric fluids for metallized PP film capacitors. Of these, the most desirable appears to be that of low swellability of the PP film when in contact with the fluid. Such low swelling effect minimizes the loosening of the metallized layer which decreases the capacitance of the capacitor with the passage of time. Another property is that of its gas absorption ability. Good gas absorption ability assures that any gases that are evolved within the capacitor are absorbed by the dielectric fluid.